Web feeding correction device



Oct. 9, 1962 R. ZUROWSK! 3,057,293

WEB FEEDING CORRECTION DEVICE Filed Jan. 10, 1961 5 Sheets-Sheet l FIG.

INVENTOR. RUDOLPH L. ZUROWSKI A T TORNE Y Oct. 9, 1962 Filed Jan. 10, 1961 FIG.

R. ZUROWSKI 3,057,293

WEB FEEDING CORRECTION DEVICE 5 Sheets-Sheet 2 6 k J A I/IIIIIIIIII'" 1962" R. 1.. ZUROWSKI 3, ,2

WEB FEEDING vCORRECTION DEVICE Filed Jan; 10, 1961 5 Sheets-Sheet a FIG. 3

Oct. 9, 1962 R. 1.. ZUROWSKI WEB FEEDING CORRECTION DEVICE 5 Sheets-Sheet 4 Filed Jan. 10, 1961 FIG. 4

FIG. 7

Oct. @9, .1962 R. ZUROWSKl WEB FEEDING CORRECTION DEVICE Filed Jan. 10, 1961 5 Sheets-Sheet 5 3,057,293 WEB FEEDING RRECTION DEVICE Rudolph L. Zurowski, Endicott, N.Y., assignor to International Business Machines Corperation, New York, N.Y., a corporation of New York Filed Jan. 10, 1964, Ser. No. 81,747 12 Claims. (all. 1tlI---336) This invention relates to feeding devices and particularly to a correction device for controlling the alignment of a moving web.

While not necessarily limited thereto, the present invention is particularly related to a means for correcting the alignment of an ink ribbon useful in a printer apparatus.

In on-the-fly printers of the type commonly referred to as a chain printer, a plurality of uniformly distributed type members are movable along a print line opposite which are positioned a plurality of uniformly spaced print hammers selectively operated to strike predetermined ones of the type members at predetermined printing positions along the print line.

In a chain printer of the type referred to as a back printer, a print couple comprising an ink ribbon and a print medium strip are fed between a plurality of such type hammers and the type members. The imprint in the print medium is obtained by striking the print medium and ribbon against the moving type members of the chain.

In one embodiment of such a printer, the type elements are moving along a horizontal print line while the print medium and ink ribbon are fed transversely to the direction of type motion, the print medium being fed preferably step by step and the ink ribbon being fed continuously. Under such conditions of operation the ribbon due to frequent contacts with the type members is subjected to a lateral drag force which causes misalignment. Such misalignment left uncorrected eventually produces poor print quality and jamming of the ribbon feed device. Previous correction devices and techniques for maintaining the alignment of the transversely fed ribbon have proved unsatisfactory. Wrinkling and creasing of the ribbon followed by cutting on impact with the embossed metal type characters resulting in defective printing and printer operation frequently resulted.

It is therefore an object of the present invention to provide means for eliminating or reducing the above defects and disadvantages.

It is a more particular object of the present invention of providing means for correcting for misalignment of a continuously fed web such as an ink ribbon which is subjected to misaligning forces during feeding.

It is a further object of the present invention to provide means for correcting for misalignment of an ink ribbon being fed in a printer device.

It is a still further object of this invention to provide a web correction device which is simple and operably reliable.

These and other objects are attained in accordance with the present invention by providing a correction device which periodically subjects a continuously moving web to a force transverse to its direction of motion in opposition to a counter transverse force causing it to be displaced from a lateral home position. In general the correction device of the present invention comprises means for detecting the presence or absence of a moving web from a lateral home position, aligning means for applying a force restoring the web to the lateral home position in opposition to a lateral disaligning force, means for periodically initiating the operation of the detection and restoring means in timed relation with the advance of the web.

tes atent O 3,057,293 Patented Oct. 9, 1962 In the preferred embodiment the detection means is a lever mechanism carrying a mechanical sense element positionable to rest on a guide member for the moving web. The sense element assumes either of two positions dependent on the presence or absence of the web at the home position. In accordance with the position taken by the sense element, the lever mechanism will assume corresponding first and second positions. An interposer means operated on by the detection lever is adapted to enable or disable a restore mechanism adapted to apply a restoration force to the moving web. In the preferred form the restoration mechanism is a pivotally mounted lever mechanism carrying a friction roller having its axis of rotation skewed relative to the direction of force for advancing the web. Both the detection and the restoration mechanisms are operated periodically by the cyclically operated portions of the ribbon or web drive mechanism.

It will be appreciated that a correction device has been provided which is simple in construction, reliable in operation, and which is eifective when incorporated in an on-the-fly printer to eliminate wrinkling of the ink ribbon web so as to attain improved print quality.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying draw: ings.

In the drawings:

FIG. 1 is an isometric view of a printer apparatus showing a ribbon feed device incorporating the present invention.

FIG. 2 is an elevation view of a portion of FIG. 1 showing the ribbon feed and alignment device of the pres ent invention in one condition of operation.

FIG. 3 is the same as FIG. 2 showing a second condition of operation.

FIG. 4 is an end elevation of the correction device of the present invention as seen from the right of FIG. 2.

FIG. 5 is an elevated view of the ribbon detection mechanism of the correction device as shown in FIG. 2.

FIG. 6 is an elevated view of the ribbon restoring mechanism of the correction device as shown in FIG. 2.

FIG. 7 is a time chart showing the operation sequence of the detection and restoring mechanisms of the present invention.

Referring to FIG. 1, a printer apparatus is shown comprising an endless chain belt 10 carrying a plurality of equally spaced type members 11 thereon. The chain belt 10 may be part of a cartridge assembly which includes spaced apart gear members 12, one of which may be driven by a suitable power mechanism (not shown) and chain guide plates 13. A record strip 14 is adapted to pass from supply roll 15 over strip guide members 16 and 17 and to be advanced step by step by conventional means including sprocket wheels 18 connected to drive pulley 19.

Printing of characters represented by the type members '11 on record strip 14 is accomplished by a plurality of type hammers 20 equally spaced at a plurality of print positions along a print line parallel to the path of travel of the chain belt 10. The operation of the hammers 20 is preferably under control of a system adapted to identify the various type members 11 as they appear at predetermined print positions and a storage device which identifies the character to be printed at the corresponding print posi-' tridge plate 13 forward and rearward guide plates 24 and 25 to winding roll 26. The feeding of the ribbon 21 is effected by a constant speed electric motor 27 connected by shaft 28 to a reduction gear 29 through gears 30 and 31 connecting reduction gear 29 to ribbon roll drive gears 32 and 33 on shafts 34 and 35 respectively.

In the environment in which the present invention is understood, the feeding of ribbon 21 is continuous. The ribbon 21 also moves past the print line transverse to the direction of movement of the chain belt 10. In the con templated use of the present invention, the type chain is continuously moving and printing occurs on-the-fly, i.e., the type hammers 20 strike the strip 14 (Which is stationary during printing) and moving ribbon 21 against the moving type 11. Each time the ribbon 21 contacts the moving type members 11, an instantaneous force is applied to the ribbon 21 causing it to advance laterally. Where the printing occurs at a high number of operations per second such as where a large number of print hammers 20 is employed, the net effect is to apply a substantially continuous lateral or drag force to the ribbon 21 tending to displace it laterally.

- To compensate for the lateral displacement of the ribbon 21 means is provided for restoring it to a predetermined lateral or home position at periodic intervals during the feeding of the ribbon 21 from roll 22 to roller 26. The mechanism for accomplishing this may be seen by reference-to FIGS. 1 through 6.

The restoring mechanism comprises a lever 40 mounted on a stationary pivot 41 and carrying at its upper end a friction restoring roll 42. Friction roll 42 is mounted by shaft 43 to a bracket 44 which is attached to the upper end of lever 40 by such means as a bolt 45 or the like. The shaft 43 of friction roll 42 is skewed relative to the direction of travel of ribbon 21. Thus, the force applied to the ribbon to effect its windup on roll 26 is converted through skewed roll 42 to a lateral restoring force oppos ing the displacement force of type chain 10. Guide plate 25 under the ribbon 21 serves to back up the friction roll 42 when lever 40 is rotated counterclockwise about its pivot 41. A spring 46 is anchored at one end to a frame 47 and is connected at the other end by pin 48 to the lower arm of lever 40 and operates to bias lever 40 toward contact with the ribbon 21 on guide plate 25. The lower end of restore lever 40 is provided with a curved edge 49 adapted to be cam operated to rotate lever 40 around pivot 41 against the bias of spring 46. Intermediate its ends, restore lever 40 is bent to provide a stop or lock edge 50. The friction roll 42 may be provided with a ratchet 51, and a pawl 52 mounted on bracket 44 is cooperable with ratchet 51 to prevent the reverse rotation of roll 42 when the direction of motion of the ribbon 21 is reversed should such be desired.

As was previously stated, the restoration of the ribbon 21 to a predetermined lateral home position is performed periodically if needed. The means for detecting the displacement of the ribbon 21 from the lateral home position comprises a detection lever 54 supported at one end by stationary pivot 55 and carrying at its other end a detection element 56 freely rotatable about a horizontal shaft 57. The detection lever 54 is provided intermediate its ends with a downwardly extending arm 58 having a curved camming edge 59 adapted when engaged to effect the rotation of the detection lever 54 clockwise around pivot 55. The upper end of detection lever 54 is preferably contoured so as to have its counterclockwise rotation limited by pivot 41 of restore lever 40. A pawl 60 is mounted to fixed pivot 61, which is suitably anchored to frame 47. A leaf spring 62 connected to the pawl 60 by screw 63 extends ovei the upper end of the pawl and beyond its left end. A detent 64 in the lower left end of pawl 60 is provided for engaging the stop section 50 of restore lever 40. A pin 65 attached to the inner surface of detection lever 54 extends outwardly to be engageable when rotated clockwise with the under side of leaf spring 62.

. The operation of the detection and restoring mechanisms is performed in timed relation with the feeding of 4 ribbon 21. For this purpose a cam roll 70 is mounted on the face of reduction gear 29. As reduction gear 29 rotates counterclockwise, roller 21) is brought successively into contact with cam surface 59 of detection lever 54 and cam surface 49 of restore lever 40.

The operation of the correction device of the present invention can be understood more clearly in connection with reference to FIG. 7. Assuming that the sense element 56 is resting on the upper surface of guide member 25 and ribbon 21 has been displaced from its lateral position where it would be in contact with the sense element 56, assuming further that friction roll 42 has been placed on the upper surface of ribbon 21, the detection and restoring mechanisms of the correction device is as shown in FIG. 2. At that time the interpo-ser pawl mechanism 61b is elevated by pin 65 on detection lever 54 so that notch 64 is above stop edge 50 of restore lever 49. As ribbon 21 is wound on roll 26, the cam roll 70 on gear 29 is caused to be rotated counterclockwise until such time as the surface of roller 70 contacts cam surface 59 on arm 58 of detection lever 54. Assuming that ribbon 21 has been restored to its lateral home position so that it is in contact with sense element 56 when cam roller 70 engages camming surface 59 of detection lever 54, the lever 54 will be lifted so that sense element 56 is elevated above the surface of guide plate 25. As cam roller 71 continues to rotate, it will pass beyond cam surface 59 causing lever 54 to rotate counterclockwise to lower sense element 56 onto the upper surface of ribbon 21. At that instant, the motion of the ribbon 21 produces a turning of element 56 so that it no longer supports the upper end of lever 54. Lever 54 will continue to turn counterclockwise until the contoured portion thereof engages pivot 41. Pin 65 carried by lever 54 will have been dropped to a position where it no longer engages the under side of spring 62 on pawl 60. The action just described is illustrated in FIG. 7 in curve I by the portions and 81 respectively. As the gear 29 continues to rotate from the position where it engaged camming surface 59 and beyond it some interval later, for example, 120 of rotation, roller 70 comes into contact with surface 49 of restore lever 40. At that time, friction roll 42 is in contact with the upper surface of ribbon 21 and is applying a restoring force toward the lateral home position. The continued rotation of gear 29 causes roller 70 to move across surface 49 of restore lever 40 causing it to rotate clockwise around pivot 41 against the action of spring 46 lifting roller 42 out of contact with the ribbon 21. By rotating the lever 40 clockwise about pivot 41 roller 711 moves the locking edge 50 of lever 40 to the left a sufficient degree to permit the pawl 65 to move counterclockwise around pivot 61. Thus, the notch 64, since there is no support of the pawl by pin 65 through spring 62 will drop below the edge 50 of lever 40. As the roller 70 advances beyond the cam surface 49 of lever 40, spring 46 applies a biasing force causing lever 40 to be rotated in a counterclockwise direction. However, notch 64 of pawl 60 is in position to engage stop surface 50 thereby preventing the rotation of lever 40 so that friction roll 42 remains out of contact with ribbon 21. The correction device mechanisms are now in the condition illustrated in FIG. 3 and the operation of the restoring device just described is illustrated in FIG. 7 by sections 87, 84, and of curve II.

Assuming that the ribbon has now been displaced laterally from its home position so that sense element if dropped on guide plate 25 would not come in contact with the ribbon as gear 29 completes its first revolution and is approaching 360 on the time chart of FIG. 7, a cycle of operations is performed which will initiate the restoration of the ribbon to its lateral home position. First cam roll 70 on gear 29 contacts cam surface 59 on lever 54. The upper end of the lever 54 is rotated clockwise and sense element 56 which is freely rotatable on pivot 57 is caused to rotate clockwise and to be held in a substantially vertical position. Pin 65 engages the lower edge of leaf spring 62 and causes it to be flexed clockwise about its point of r attachment on pawl 63. The pawl 60, however, is not free to rotate clockwise with the spring 62 around pivot 61 since notch 64 is in contact with surface 50 of restore lever 40 which is biased by spring 46. As roller 70 moves under camming surface 59 of lever 54, it permits the lever 54 to rotate counterclockwise until sense element 56 comes to rest on the upper surface of guide member 25. Since ribbon 21 is not in its lateral home position, sense element 56 will retain the lever 54 in a higher position indicated by section 83 in curve I. Thus the detection lever 54 is in position calling for the application of a restoring force by the friction roll 42. However, such application must await the rotation of cam roller 70 through approximately 120 where it comes into contact with cam surface 49 of lever 40. As a result of such action, restore lever 40 is first rotated clockwise about pivot 41 against the bias of spring 46. At thistime, pawl 60 is released from contact with locking surface 50, consequently, pawl 60 will turn clockwise about pivot 61 to follow its leaf spring 62 which has been previously deflected by pin 65 of lever 54. As indicated in section 86 of curve II in FIG. 7, roller 70 moving beyond the point of contact with surface 49 of lever 40 causes the restore lever 40 to rotate counterclockwise around pivot 41. The friction roll 42 is thus lowered into contact with the upper surface of ribbon 21 and operates to convert the translational force applied to the ribbon to a lateral displacement force which restores the ribbon to the lateral home position. This operation is indicated in section 86 of curve II, FIG. 7. On the next cycle of roller 70, the first described operation is repeated if the ribbon 21 has been fully restored to its lateral home position.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In an apparatus having a ribbon element or the like and means for moving said ribbon at a continuous rate of travel in a first direction past a work station, said: ribbon element being subjected to a disaligning force transverse to the direction of travel of said ribbon, means for correcting for the disalignment of said ribbon comprising a sensing mechanism periodically operable in timed relation with the advance of said ribbon element for sensing the displacement of said moving ribbon element from a lateral home position, and means operable in response to an absence indication by said sense means for restoring said moving ribbon to said lateral home position in opposition to said disalignment force.

2. In an apparatus having a ribbon element or the like and means for moving said ribbon at a continuous rate of travel in a first direction past a work station, said ribbon element being subjected to a disalignment force transverse to the direction of travel thereof, means for correcting for the disalignment of said ribbon comprising a means operable for detecting the presence or absence of said moving ribbon element from a home position, means operable for restoring said ribbon to said home position in accordance with an absence indication from said detection means, and means for periodically initiating the operation of said detection and restoring means in timed relation to the advance of said ribbon element.

3. In an apparatus having a ribbon element or the like and means for moving said ribbon at a continuous rate of travel in a first direction past a Work station, said ribbon element being subjected to a disalignment force transverse to the direction of travel thereof, means for correcting for the disalignment of said ribbon element comprising means operable for detecting the presence or absence of said moving ribbon element from a lateral home position, means operable for restoring said ribbon to said home position in opposition to said disalignment force, means for periodically initiating the operation of.

said detecting and restoring means in timed relation with the advance of said ribbon element, and means responsive to said detecting means for enabling or disabling the operation of said restoring means in accord ance with an absence or presence indication by said detecting means.

4. In an apparatus having a ribbon element or the like and means for moving said ribbon at a continuous rate of travel in a first direction past a work station, ribbon element being subjected to a disalignment force operable transverse to the direction of travel of said ribbon, means for correcting for the disalignment of said ribbon element comprising detection means operable for detecting the presence or absence of said ribbon from a lateral home position including a detection lever and a sense element carried thereby, said detection lever being positionable to place said sense element at said lateral home position, means for applying a restoring force in opposition to said disalignment force including a restore lever and a roller carried thereby, said lever being movable for placing said roller into Opposition force applying contact with said ribbon, means for periodically opera-ting said detection lever and said restore lever in succession in timed relation with the advance of said ribbon for successively placing said sense element in said home position and for positioning said restore lever in preparation for the application of said roller to said ribbon, and means controlled by said detection means for enabling and disabling said restore means including a pawl mechanism operable by said detection lever for freeing or in hibiting said restore lever for movement effective to apply said restore roller to said ribbon in accordance with the condition of said detection lever determinable by said sense element.

5. In an apparatus having a ribbon element or the like and means for moving said ribbon at a continuous rate of travel in a first direction past a work station, said ribbon element being subjected to a disaligning force transverse to the direction of travel of said ribbon, means for correcting for the disalignment of said ribbon comprising detection means operable for determining the absence or presence of said ribbon from a lateral home position including a detection lever movable to first and second positions and a sense element carried thereby, said sense element being deflectable by said moving ribbon to control the movement of said detection lever from said first to said second control positions, means for restoring said ribbon to said home position including a lever movable so as to assume first and second restoring positions and a restore force applicator carried thereby, means for periodically initiating the movement of said detection lever and said restore lever in timed relation with the advance of said ribbon whereby said sense element is placed at said home position and said restore lever is prepared for placing of said roller on said ribbon, and means controlled by said detection lever for enabling and disabling the operation of said restoring means including a pawl mechanism movable to first and second positions to free and lock said restore lever in accordance with the control position assumed by said detection lever under the control of said sense element.

6. In a printer apparatus having a printing mechanism including type elements movable at a continuous rate of speed along a print line, hammer elements arranged along said print line and being operable for striking said moving type elements, and a ribbon element movable transverse to the direction of motion of said type elements and adapted to be moved by said hammer elements into repetitive contact with said type elements, the combination comprising means for advancing said ribbon element in a direction transverse to said print line at a continuous rate of travel, and means operable periodically by said ribbon advancing means in timed relation with the advance of said ribbon element for correcting for the disalignment of said ribbon from a lateral home position.

7. In a printer apparatus having a printing mechanism including type elements movable along a print line, hammer elements arranged along said print line and being operable for striking said moving type elements, and a ribbon element movable transverse to the direction of motion of said type elements and adapted to be repetitively brought into frictional contact With said type elements by said hammer elements, the combination comprising means for advancing said ribbon element transverse to the direction of motion of said type elements, means for detecting the presence or absence of said ribbon element from a home position, and means for restoring said ribbon to said home position in opposition to disalignment caused by contact of said ribbon and said moving type elements, said detection means and restoring means being operable by said ribbon advancing means in timed relation with the advance of said ribbon.

8. In a printer apparatus of claim 7 in which said restoring means includes a means for converting the force for advancing said ribbon past said print line into a restoring force transverse to the direction of advance of said ribbon.

9. In a printer apparatus of claim 8 in which said force conversion means includes a roller means frictionally engaging a surface of said ribbon element at a point beyond said contact with said type element, said roller means having an axis of rotation displaced at an angle to a line transverse to the direction of travel of said ribbon.

10. In an apparatus having a ribbon element or the like the combination comprising means for advancing said ribbon at a continuous rate of travel in a first direction past a Work station, said ribbon element being subjectable at said work station to a disaligning force transverse to said direction of travel, means operable for detecting the presence or absence of said advancing ribbon element from a lateral home position, means operable for restoring said ribbon to said home position in accordance with an absence indication from said detecting means, and means operable by said ribbon advancing means for periodically initiating the operation of said detection and restoring means in timed relation with the advance of said ribbon element.

11. In an apparatus having a ribbon element or the like in accordance with claim 5 in which said means for pe riodically initiating the movement of said detection lever and said restore lever in timed relation With the advance of said ribbon includes means operable by said ribbon moving means.

12. In an apparatus having a ribbon element or the like in accordance with claim 11 in which said means operable by said ribbon moving means includes a cam member adapted to actuate said detection lever and said restore lever in succession and in timed relation with the advance of said ribbon.

References Cited in the file of this patent UNITED STATES PATENTS 642,141 Lyon Jan. 30, 1900 1,769,687 Hamilton July 1, 1930 1,995,462 Tandel Mar. 26, 1935 2,297,858 Andreotto Oct. 6, 1942 2,485,254 Brewster Oct. 18, 1949 

